In recent years, the electronics industry has invested substantially in time and money in bubble device technology which is used in advanced computer hardware. The attraction for this investment has centered on the expectation of a rapidly expanding bubble memory market. These devices serve to span the gap between expensive semiconductors and the mechanically sensitive magnetic disks and tapes used in computer technology.
The substrate wafer material for these bubble memory devices is composed of a stoichiometric composition of gadolinium-gallium oxides, Gd.sub.3 Ga.sub.5 O.sub.12, commonly referred to as gadolinium-gallium garnet or GGG. Current fabrication techniques for these wafers result in the generation of the order of 80% GGG by-products that are based on relatively expensive starting materials. A method for the recovery and separation of high purity oxides from the GGG by-products so that the material could be re-used in the process in a practical manner would aid significantly the economics of production of GGG wafers.
While the problem of by-product recovery and purification has existed for a number of years in the industry, and attempts to recover by-products have been reported such as the means that involves digesting the scrap material, precipitating the gadolinium and electrolytically depositing the gallium as described in U.S. Pat. No. 4,198,231, the search continues for a more satisfactory, practical way for efficiently recovering the by-product in an economically attractive manner for an industrial size facility. In view of the substantial economies involved, a need exists for improved means to recover gadolinium and gallium from the GGG wafer fabrication by-products.